Circuit-breaker.



P. H. THOMAS.

CIRCUIT BREAKER.

APPLICATION FILED DEG.10, 190s. RENEWED 213.19, 1907.

95%,153. Patented Mar. 15,1910:

UNITED STATES PATENT OFFICE.

PERCY H. THOMAS, OF PITTSBURG, PENNSYLVANIA, ASSIGNOR TO COOPER HEWITTELECTRIC COMPANY, OF NEW YORK, N. Y., A. CORPORATION OF NEW YORK.

CIRCUIT-BREAKER.

Application filed December 10, 1903, Serial No. 184,540. RenewedFebruary 19, 1907.

To all whom it may concern:

Be it known that I, PERCY H. THOMAS, a citizen of the United States, andresident of Pittsburg, county of Allegheny, State of Pennsylvania, haveinvented certain new and useful Improvements in Circuit-Breakers, ofwhich the following is a specification.

In an application for Letters Patent of the United States filed by me011 the 27th day of June, 1903', Serial Number 163,307, I have shown anddescribed a form of circuit-breaker especially adapted for use inconnection with alternating current circuits, the significant featurebeing that the circuit is broken between surfaces inclosed in anexhausted chamber. Vhen such a circuitbreaker is included in analternating current circuit, the rupture of the arc takes place when thecurrent momentarily ceases at the zero point of the wave, and cannotstart again, this being accomplished without any injurious rise ofpotential in the external circuit. The described circuit-breaker mayalso be applied to circuits conveying currents naturally varying,provided the lower limit of variation is below the carrying limit of thecircuit-breaker.

In this application I disclose a circuitbreaker which may also beutilized in connection with alternating current circuit, but which ismore particularly adapted to be used in connection with direct currentcircuits.

In the present instance, the interruption of the circuit is accomplishedby the gradual introduction of a resistance to the flow of currentthrough increasing the pressure within the exhausted chamber. In gas orvapor apparatus of this character, the resistance to the flow ofcurrent, or, in other words, the voltage necessary to pass current, isgreatly increased as the pressure of the vapor within the exhaustedchamber rises. Apparatus of this class will not pass current below acertain definite limit of electro-1notive-force, and when the chamber ismade of a proper heat radiating and heat absorbing capacity, this limitmay be so fixed that while a normal current will flow through theapparatus, an abnormal current will be prohibited from passing throughand the current will cease. In this connec tion it is to be rememberedthat the pressure in the exhausted chamber is determined by thetemperature of the vaporizable material Specification of Letters Patent.

Patented Mar. 15, 1910.

Serial No. 358,217.

within the chamberusually mercury which is heated by the passage ofcurrent. It becomes, then, a question of properly proportioning thedimensions of the chamber so as to give it a definite heat radiating andheat absorbing capacity. This done, a vapor circuit-breaker may be madeto operate with certainty within such limits as may be pre determined.

My invention is illustrated in the accompanying drawings, in whichFigure 1 is a longitudinal section of a circuit-breaker constructed inaccordance with my invention; Fig. 2 shows the same circuitbreakcr inits open position; and Fig. 3 illustrates a modification.

Referring to Figs. 1 and 2, 1 is a container of insulating materialhaving lead wires, 2 and 3, sealed into its ends, the said lead wiresbeing connected inside the container by a mass of mercury, i. Thisconnection by means of mercury or some equivalent conducting liquidexists when the circuitbreaker occupies its closed position, asillustrated in Fig. 1. The circuit-breaker, thus horizontally located,may be assumed to constitute part of an electric circuit, and under suchcircumstances to convey the normal current after the manner of anyordinary circuit controller, in its closed position. When it is desiredto open the circuit, the circuitbreakcr is turned into the positionillustrated in Fig. 2, whereby the mercury or other conducting liquid isseparated into two distinct masses or bodies, 8 and 9, located at theopposite ends of the circuitbreaker and constituting electrodes. Toenable the circuit-breaker to be manipulated in the manner indicated,the same may be mounted upon trunnions, one of which is shown at 5.

In order to tip the circuit-breaker to cause the rupture of the circuitby the gradual introduction of resistance, as indicated in the statementof the invention, the container 1 and the condensing chambers, 6 and 7,if such chambers are used, should be so proportioned that the currentwhich may traverse the apparatus after the tilting of thecircuit-breaker will heat one or both of the electrodes sufliciently toproduce an increased vapor pressure such as will reduce the currentstrength below the operating minimum. It is obvious that by tipping thecircuit-breaker more or less, as the case may be, the vapor pressurewithin the apparatus may be varied at will within wide limits.

In Fig. 3, the circuit-breaker is arranged in shunt to a switch ofcomparatively low resistance which carries the normal current of thecircuit. In this type of circuitbreaker the container 11 is made ofcomparatively small cross section and contains in the major portion ofits length a small amount of mercury bridging the electrodes 12 and 13at the opposite ends of: the circuit-breaker. I may provide smallcondensing chambers, 14 and 15, above the respective electrodes.

The switch which carries the normal current is shown at 16, and whenthis switch is opened, the entire normal current is diverted through thecircuit-breaker, where upon a portion of the mercury in the con tainer11 is vaporized, creating a high vapor pressure for the purposes alreadyset forth.

The circuit-breaker shown in Fig. 3 does not require to be provided withpivots, inasmuch as it retains its horizontal position under allcircumstances, depending upon the vaporization of a portion of the thinlayer of mercury in the main portion of the tube to secure the resultsindicated.

It. is found that in both types of circuitbreaker illustrated herein,the development of high vapor pressure is gradual; that is to say, thepoint of actual rupture of the circuit is reached through comparativelysmall gradations. Accordingly, all tendency to create an injurious riseof potential in the external circuit is avoided.

The structure illustrated in Fig. 8 is not specifically claimed herein,but is claimed in applicants Patent #876,918, dated January 14 1008.

1 claim. as my invention:

1. The combination with an electric circuit, ol' a vapor circuit-breakerincluded therein, and means whereby the circuitbreaker may be moved foropening the circuit within the circuit-breaker, the proportions of thecircuit-breaker being such that when it is moved to open position thevapor is gradually heated beyond its carrying capacity for the normalcurrent.

2. The combination with an electric cir cuit, ot' a gas or vaporelectric circuit breaker included therein, said circuit breaker beingadapted to heat up beyond the conducting point on the passage of normalcurrent through the vapor path, and means within the container for shortcircuiting said vapor path together with trunnions permitting motion ofsaid circuit breaker to discontinue the short circuiting means.

3. A or vapor electric circuit breaker adapted to heat up beyond theconducting point on the passage of normal current through the vapor pathcomprising means for short circuiting said vapor path within thecontainer and means for tilting the container to interrupt said shortcircuit.

l. In a vapor electric device, the combination with two electrodesspaced apart and adapted to contact with each other of a her meticallysealed and completely exhausted container inclosing the same, saidcontainer being so proportioned as to cause a rise of temperature andcorresponding rise in pressure above the conducting point when currentpasses through the exhausted space between the electrodes.

Signed at New York, in the county of New York and State of New York,this 7th day of December, A. D. 1903.

PERCY TI. THOMA S.

Vitnesses WVM. H. Caren, (luoacu H. S'rooiunn'min.

